Simplify the following expression: $\sqrt{250}-\sqrt{160}+\sqrt{40}$
First, try to factor any perfect squares out of the radicals. $= \sqrt{250}-\sqrt{160}+\sqrt{40}$ $= \sqrt{25 \cdot 10}-\sqrt{16 \cdot 10}+\sqrt{4 \cdot 10}$ Separate the radicals and simplify. $= \sqrt{25} \cdot \sqrt{10}-\sqrt{16} \cdot \sqrt{10}+\sqrt{4} \cdot \sqrt{10}$ $= 5\sqrt{10}-4\sqrt{10}+2\sqrt{10}$ Finally, simplify by combining the terms. $= ( 5 - 4 + 2 )\sqrt{10} = 3\sqrt{10}$